Substantially two types of specimen receptacles are known for retaining specimens of different dimensions, for example on the specimen stage of a microscope, namely specimen clamps, which are mounted in the form of springs on the specimen stage and retain the specimen, usually a specimen carrier, on the stage. Also known is a specimen holder made up of two plates displaceable with respect to one another, according to DE 30 28 154 A1 (corresponding to U.S. Pat. No. 4,436,385). According to this document, two plates are mounted on the specimen holder, with the sides of these mutually facing plates movable toward and away from one another, i.e. displaceable in opposite directions. The mutually facing sides of the plates are equipped with indentations, so that an opening is created when the plates are slid toward one another. Each indentation additionally contains a setback onto which the specimen, for example a cylindrical or rectangular specimen carrier, can be placed. The specimen carrier is in turn held in the lateral direction by notches in the setbacks. Because the plates are braced against one another by frictional engagement with their guides or by spring force, the specimen is clamped in place with the aforesaid notches. Cylindrical specimens are in most cases retained using notches that extend tangentially to the outer specimen edge, while rectangular specimens are in most cases retained with notches that make contact against the corners of the specimen. The opening produced by the indentations in the plates is suitable, in particular for transmitted-light microscopes, for transilluminating the specimen. The specimen itself then lies on the setback at the edge of the two plates and is, as already discussed, retained laterally by means of the notches.
The aforesaid specimen holder according to DE 30 28 154 A1 has the disadvantage that the guiding and mutual clamping of the plates results in a complex design for the specimen holder, with which, furthermore, only a very limited number of specimens of different cross-sectional geometries can be retained. To allow the known specimen holders to be used for a larger number of specimen carriers, an exchange of plates having different notches would be necessary. This is complex, however, since for guidance and for mutual clamping the plates are captured in grooves that make disassembly considerably more difficult.
The aforementioned spring clamps are unsuitable for specimens such as Petri dishes, microtitration plates, or multi-well plates, since these specimens are too tall and their dimensions are too varied.